As business activities come to rely more and more on information systems, losses associated with system shutdowns are becoming enormous. As a result of this, greater importance is being attached to technologies that do not shut down a system or rapidly restore a system when deficiencies such as a system failure or damage occur.
For example, storage cluster technology is disclosed in Patent Literature 1. In storage cluster technology, data in a first logical volume of a first storage system is copied to a second logical volume of a second storage system. In a case where a failure occurs in the first storage system, a host computer is able to access the data in the second logical volume of the second storage system by switching from an access path to the first logical volume to an access path to the second logical volume. Furthermore, in the following explanation, a combination of the logical volume that is the data copy source (copy source volume) and the logical volume that becomes the data copy destination (copy destination volume) will be called a “remote copy pair”.
Also, in Patent Literature 2, disaster recovery technology for rapidly restoring a system in a case where the entire system at a site shuts down due to a disaster or the like is disclosed. According to the disaster recovery technology, a remote copy pair comprising a first logical volume of a first storage system and a second logical volume of a second storage system, which is used when the first storage system is unable to be used, is configured. This enables the second storage system to continue operating even when the first storage system has been damaged. Furthermore, in the following explanation, a first storage system that is run during normal operations may be called a “primary storage system”, and a second storage system that is used in place of the first storage system may be called a “secondary storage system”.